July 21, 2017
Brain tumors are described differently than tumors found in other parts of the body. A tumor can be benign or malignant. A benign tumor is not cancer, and it will not spread, but it can still grow and put pressure on tissue in the brain. This pressure may damage healthy brain tissue and interrupt normal functions of the brain, interfering with vital functions, such as breathing or heart rate, and cause death.
Normal Anatomy and the Development of Brain Tumors
The brain and spinal cord make up the central nervous system (CNS). The CNS affects all of the body, interpreting sensory information, and regulating certain functions like body temperature, digestion, and coordinating physical movements. The brain is also responsible for memory, learning, and emotions.
The three main areas of the brain include:
- The cerebrum is the control center for thought, reason, and speech. It houses the emotional center of the brain, and is divided into two large hemispheres, the right and left.
- The cerebellum primarily coordinates movement and balance, and is found at the back of the head near the base.
- The brain stem is the back and bottom portion of the brain that connects to the spinal cord. It allows nerves to transmit messages back and forth to the brain. There are three parts to the brain stem— the pons, medulla oblongata, and midbrain. These structures control involuntary actions, such as breathing, digestion, and heart function.
Cell division and cell death are a normal process in the body to replace old or damaged cells. Sometimes this division and new cell growth can continue after it is supposed to stop, and this excess growth forms a tumor. It is unclear what causes the abnormal growth, but is often a combination of genetic and environmental factors. Brain tumors rarely spread to other areas of the body, but they can spread throughout the brain.
Types of Brain Tumors
There are two types of brain tumors – primary and secondary. Primary brain tumors start in the brain or in the layers that surround it. It is the second most common type of cancer in children and adolescents.
Secondary brain tumors are tumors that develop from cancers elsewhere in the body. Cancer cells can break from the original site of cancer and travel to the brain in the bloodstream. Also known as metastatic tumors, secondary tumors are always malignant.
The location of tumors will determine the effects and the treatment plan, and most brain tumors are named for the place in the brain where they start.
Glioblastoma Multiforme (GBM) is the most common glioma—a type of brain cancer. This cancer starts in the glial cells, which are cells that help nerve cells work. This condition can develop suddenly. It can also develop from a lower-grade, less cancerous brain tumor. Most cases are located in the cerebral hemisphere of the brain, but can also begin in the spinal cord or brain stem.
GBM originates from astrocytes, which are a type of glial cell. The factors that cause normal-functioning astrocytes to become cancerous are not well understood. GBM is more common in people over 50 years old, especially those who are Caucasian, Hispanic, and Asian. Factors that can increase your chance of developing GBM include:
- Having a low-grade brain tumor, which occasionally develops into a higher-grade tumor
- Having one of the following genetic disorders: neurofibromatosis, tuberous sclerosis, Von Hippel-Lindau disease, Li-Fraumeni syndrome, or Turcots syndrome
- History of radiation therapy
- Occupational exposures in the synthetic rubber or petroleum-refining industries
- Exposure to vinyl chloride or pesticides
- History of CT scans during childhood
Symptoms may vary depending on the location or size of the tumor. In general, symptoms may include:
- New onset headaches or seizures
- Progressive cognitive dysfunction
- Problems with vision, language, motor function, or sensation may occur
- Progressive neurological deficits, including weakness or numbness
- Personality or behavioral changes, including development of inappropriate behaviors
- Memory loss
In diagnosing a GBM, your physician needs to fully understand your symptoms and medical history, in addition to conducting a thorough physical exam. Images and scans will be taken of the brain, via CT scan, MRI scan, Functional MRI, or PET scan. Your brain activity may also be measured with a Magnetic resonance spectroscopy (MRS) scan or an Electroencephalogram (EEG). Finally, your bodily fluids and tissues will be tested and reviewed, most likely through biopsy and lumbar puncture, to assist in evaluating the cerebrospinal fluid that surrounds the brain and spinal cord.
Primary treatment for GBM begins with surgery, done to confirm diagnosis and relieve headache, but doctors often cannot completely remove the cancer, due to its microscopic size and tendency to spread undetected. After surgery, patients routinely undergo radiation therapy to further decrease the size of the tumor, chemotherapy to increase survival time and quality of life, steroids to suppress swelling in the brain, anti-seizure medications, and medication for general pain relief.
Even with aggressive treatment, few patients survive more than 5 years after diagnosis. However, there is evidence that medical and surgical intervention can increase life expectancy and improve quality of life. Unfortunately, there are no current guidelines to prevent GBM because the cause is unknown.
For more information regarding glioblastomas, or other neurological symptoms and disorders, please contact Dr. Matthew Boyce of Neurological Associates at (804) 288-2742. Dr. Boyce is currently welcoming new patients.